Create servicetemplate_usage_guide.md

Initial PR for the servicetemplate usage guide.

docs/smc/servicetemplate_usage_guide.md

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+# ServiceTemplate Usage Guide
+
+MES version21112024
+
+## Overview
+
+ServiceTemplates define reusable service configurations that can be deployed across multiple Kubernetes clusters managed by Project 2A. They support different deployment methods, including Helm charts and raw manifests.
+
+## Usage Patterns
+
+### 1\. Direct Template Usage
+
+```
+apiVersion: hmc.mirantis.com/v1alpha1
+kind: ServiceTemplate
+metadata:
+  name: ingress-nginx-v1.11.2
+spec:
+  helm:
+    chartName: mirantis-ha-ingress-nginx
+    chartVersion: 1.11.2
+```
+
+### 2\. Multi-Cluster Service Deployment
+
+```
+apiVersion: hmc.mirantis.com/v1alpha1
+kind: MultiClusterService
+metadata:
+  name: global-nginx
+spec:
+  services:
+    - name: ingress-nginx-v1.11.2
+      config:
+        controller:
+          watchIngressWithoutClass: true
+  clusterSelector:
+    matchLabels:
+      hmc.mirantis.com/managed-by: hmc
+  servicesPriority: 100
+```
+
+## Template Management
+
+### Version Control
+
+Templates follow semantic versioning (e.g., v1.11.2). Version upgrades can be managed through:
+
+1. Template chains  
+2. Direct template updates  
+3. Multi-cluster service configurations
+
+### Access Control
+
+```
+apiVersion: hmc.mirantis.com/v1alpha1
+kind: TemplateManagement
+metadata:
+  name: template-access
+spec:
+  allowedNamespaces:
+    selector:
+      matchLabels:
+        environment: production
+  serviceTemplateChains:
+    - name: ingress-nginx-chain
+
+```
+
+## Priority and Conflict Resolution
+
+* Use `servicesPriority` to manage template precedence  
+* Lower numbers have higher priority  
+* Set `stopOnConflict: true` to prevent conflicting deployments
+
+## Status Monitoring
+
+Monitor service deployment status through:
+
+```
+kubectl get multiclusterservice <name> -o yaml
+```
+
+Status conditions include:
+
+* Ready  
+* SveltosClusterProfileReady  
+* FetchServicesStatusSuccess
+
+## Best Practices
+
+* **TBD**
+
+## Common Operations
+
+### Create New Template
+
+```
+kubectl apply -f service-template.yaml
+```
+
+### Update Existing Service
+
+```
+kubectl patch multiclusterservice <name> --patch '{"spec":{"services":[{"name":"new-template"}]}}' --type=merge
+```
+
+### Remove Service
+
+```
+kubectl delete multiclusterservice <name>
+```
+
+# ServiceTemplate Additional Notes
+
+## Template Lifecycle Management
+
+### ServiceTemplateVersion
+
+```
+apiVersion: templates.hmc.mirantis.com/v1alpha1
+kind: ServiceTemplateVersion
+metadata:
+  name: example-service-v1
+spec:
+  template:
+    name: example-service
+    version: "1.0.0"
+  parentVersion: ""
+  configuration:
+    helm:
+      repository: "https://example.com/charts"
+      chart: "example-service"
+      version: "1.0.0"
+    parameters:
+      required:
+        - name: replicaCount
+          type: integer
+          description: "Number of replicas"
+          default: 1
+
+```
+
+### ServiceTemplateUpgrade
+
+```
+apiVersion: templates.hmc.mirantis.com/v1alpha1
+kind: ServiceTemplateUpgrade
+metadata:
+  name: upgrade-to-v2
+spec:
+  templateName: example-service
+  targetVersion: "2.0.0"
+  strategy:
+    type: Rolling
+    rolling:
+      maxUnavailable: 1
+      maxSurge: 1
+  validation:
+    timeout: 5m
+  rollback:
+    automatic: true
+    timeout: 10m
+```
+
+## Template Chains
+
+### Chain Definition
+
+```
+apiVersion: hmc.mirantis.com/v1alpha1
+kind: ServiceTemplateChain
+metadata:
+  name: service-chain
+spec:
+  templates:
+    - name: service-v1.0.0
+    availableUpgrades:
+      - name: service-v1.1.0
+      - name: service-v1.2.0
+```
+
+## Integration with ManagedClusters
+
+### Adding Services to ManagedCluster
+
+```
+apiVersion: hmc.mirantis.com/v1alpha1
+kind: ManagedCluster
+metadata:
+  name: example-cluster
+spec:
+  template: aws-standalone-cp-v1.1.2
+  serviceTemplates:
+    - name: ingress-nginx-v1.11.2
+      config:
+        controller:
+          watchIngressWithoutClass: true
+```
+
+### 
+
+```
+
+```
+
+## Operational Guidelines (needs further testing)
+
+### Monitoring Template Status
+
+```
+# View template status
+kubectl get servicetemplate -n hmc-system
+
+# View upgrade status
+kubectl get servicetemplateupgrade -n hmc-system
+
+# View deployment status across clusters
+kubectl get clustersummary -A
+```
+
+### Health Checks
+
+```
+healthChecks:
+  liveness:
+    initialDelaySeconds: 30
+    periodSeconds: 10
+  readiness:
+    initialDelaySeconds: 10
+    periodSeconds: 5
+```